Switch lock



Aug- 2 1 c. B COATES SWITCH LOCK Filed Aug. 12

R55 BE Q .tuERm 2E:

INVEVTOR Char/is B. Coafes BY ATTORNEY Patented Aug. 20, 1929.

UNITED STATES 1,724,907 PATENT OFFICE.

CHARLES IB. COATES, F CLEVELAND, OHIO, ASSIGNOR TO CHICAGO PNEUMATIC TOOL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

SWITCH LOCK.

Application filed August 12, 1924. Serial No. 731,543.

This invention relates to control apparatus for electrical motors and machinery. In particular it concerns automatic locking means operated by one control device or switch to render a second control device or switch inoperative.

One object of the invention is to provide a simple, compact, easily operated control assembly with self contained locking mecha- 1 nism of the type described. Another ob ect is to make the actuation of the locking mechanism dependent upon the condition of the electrical circuit to be controlled. Other objects willbe apparent from the detailed description which follows.

The particular form of the invention used as an illustrative example and disclosed in the accompanying drawings is intended for use on portable electrical tools but is obviously capable of general applicat on and use.

In the drawings: x

Fig. 1 is a plan view partly in section on the line 1--1 of Fig. 2;

Fig. 2 is a vertical sectional view on the line 22 of Fig. 1 with the main or sna switch shown in elevation and the locking mechanism in operative position;

Fig. 3 is a fragmentary sectional view similar to Fig. 2 but on an enlarged scale and showing the locking mechanism in inoperative position; and

Fig. 4 is a diagrammatic showing of the elec rical circuit.

The drawings disclose what is at present believed to be the preferred form of the invention which comprises in general a unit control assembly A provided with a junction or inlet box a with which the ower cable a connects, secured in any suita le or desired manner to the casing or other portion B of the tool, motor, or other electric device to be controlled. The control assembly is housed within a casing consisting of an upper part 5 and a lower part 6, the same being secured together in assembled relation by screw bolts 7 and the lower portion 6 having a flange 8, through openings in which suitable means such as screw bolts'9 may pass to securely attach the control assembly A to the casing B of the machine to be controlled. The casing contains a plurality of control elements or switches, in the present instance, two in number, a main switch 10 and a reversing ,switch 11. The reversing switch 11 may be an extension 14 of of any suitable or desired type, that shown having a control handle 12 projecting from one side of assembly A and pivoted at 13 for limited swinging movement. Switch 11 1s by preference disposed within the lower part 6 of the casing. The main switch 10, WlllCh is by preference disposed in the upper part 5 of the casing, may be, and preferably is of the ordinary type of snap switch which being simple, compact and efficient lends itself well to incorporation in a control assembly of this type.

In order to properly house the locking mechanism for storms an important feature of the present invention, parts 5 and 6 of the switch assembly casing ave extensions 5 and 6 disposed above the path of movement control handle 12. These extensions have opposed registermg recesses to receive the locking mechanism now to be described.

Lower casing extensions 6- supports for reciprocatory movement a locking pin 14 slidingly mounted 'in a socket 6 and arranged to extend across the path of movement of p switch handle 12 to prevent throwing of the same. A coil spring 15, acting against the head of the pin,

when the main switch is ofi. Pin 14 has v magnetizable material, the upper end of which is received in a socket in a projection 5! of the upper port on of the casing when the pin is in unlocked position (Fig. 3). A solenoid coil 16 encircling pin extension 14* is seated in the recessed portions of the casing extensions 5 and 6 This coil carries a core 17 arranged magnetically to affect the extension 14" of the locking pin. The parts forming core 17 may extend outwardly beyond the coil 16 and be partly housed in opposed recesses or grooves 18 in the casing extensions 5 and 6 (Fig. 1). For usewith direct current the pin extension 14 and the core 17 may be of solid material such as soft iron, but when alternating current only is available better results are secured by making these arts of laminated material, as shown in the 'rawings, the plates of the laminar core 17 bein preferably disposed in line with the plates of the laminar extension 14 of the locking The electrical connections are such that when the main or sna-p switch 10 is actuholds the latter in its upper retracted or lnoperative position (Fig. 3)

the reversing switch, which ated by its button to the on position (Figs. 1 and 2), the electrical current is passed through the solenoid coil 16 magnetizing the laminar core or plates 17 thereof and drawing the pin extension 14:? by magnetic attraction to its lower position (Fig. 2), wherein the locking pin 14 1s projected across the path of the reverse handle 12 and revents the reversing of theelectrical mac ine. When the main switch button 10 is turned to the oil? position, the current ceases to flow through the coil 16, the core 17 loses its magnetism, and the spring 15 restores the locking pin 14 and its extension 14: to its upper inoperative or unlocking position (Fig. 3).

One arrangement of the circuit is diagrammatically illustrated in Fig. 4:, wherein main switch 10 is shown open and the reverse handle 12 in neutral position. Assuming the reverse handle 12 moved to the left and switch 10 closed the circuit leads from the positive terminal through connection 0, switch 10, connection d, solenoid coil 16, connection e, terminal f, wiper g on the re verse handle, connection it, the motor armature, connection 2', wiper g on the reverse handle, terminal j, connection is, terminal j, connection Z, the field of the motor, connection m, to the negative terminal. 'lo reverse the motor, switch 10 is opened whereupon locking pin 14 is retracted as described above and reverse handle 12 is moved to the right, whereupon on closing switch 10 the circuit connection is as followsgconnection 0, switch 10, connection (2, solenoid coil 16, connection e, terminal 7, wiper g, connection i, the armature of the motor, connection h, wiper g, terminal 3', connection Z, the field of the motor and connection m. Thus the closing of the main switch in either operative position of the reverse handle 12 sends current through the-solenoid coil 16 to force and hold locking in 14 in its locking position until the main switch is open.

As the parts of the locking mechanism and the connections thereto are entirely enclosed within the casing of the control assembly which exposes only the main switch button 10 and the reversing handle 12, there is no opportunity for the operator to tamperwith the mechanism and prevent its operation. Thus reversing of the motor while the main switch is on is efiectively prevented and possible injury to the operator and inevitable damage to the motor resulting from such lack of intelligent control is entirely avoided.

1 claim as my invention: 7

1. The comblnation with a portable electrically operated machine of control ap aratus secured to a portion of the machine comprising a casing in two parts, a control switch in each of said parts, said arts having opposed recesses adjacent t e control maaeov handle of one of said switches, and a solenoid mounted in said recesses and controlling a locking pin for said control handle.

2. In electrical control apparatus, in combination, a casing in two parts, a control switch in each of said parts, said parts having opposed recesses adjacent the control handle of one of said switches, a locking pin disposed in said recesses and arranged to be projected across the path of movement of said control handle, and electrical means under control of the other switch for controlling said pin.

3. The combination with a portable electrically operated machine of control apparatus therefor comprising a casing secured to a portion of the machine, control switches therein, said casing having a recess adjacent the control handle of one of said switches, a locking pin in said recess normally held out of the path of movement of said control handle, and electrical means also within said recess and under control of the other switch for projecting said pin into the path of said control handle to lock the same against movement.

4. In electrical control apparatus, in combination, a casing in two parts, a control switch in each of said parts, said parts having opposed recesses adjacent the control handle of one of said switches, a locking pin insaid recesses, resilient means yieldingly maintaining said pin out of the path of movement of said control handle, and a solenoid coil within said recesses and encircling an extension of said pin for moving the latter against saidresilient means to locking position.

5. In electrical control apparatus, in combination, a casing in two parts, a snap switch in the upper part and a reversing switch in the lower part, the latter having a projecting handle, extensions on both said parts of the casing above said handle, said parts having opposed registering recesses in their said extensions, a locking pin in the recess of said lower part, a spring normally holding said pin out of the path of movement of said handle, an extension on said pin, a solenoid coil disposed in said recesses and encircling said pin extension, and a core supportedby said coil in operative relation to said extension, said coil being under control of said snap switch for projecting the locking pin into locking position when the snap switch is on.

6. In electrical control apparatus, in combination, a casing in two parts, a snap' sw1tch in the upper part and a reversing switch in the lower part, the latter having a projecting handle, extensions on both said parts of the casing above said handle, said parts having opposed registering recesses in their said extensions, a locking pin in a socket of said lower part adjacent its recess,

a spring in said socket normally holding partly received in opposed grooves in said sai pin out of the path of movement 0 casing parts adjacent said recesses, said coil 10 said handle, a laminar extension on said pin being under control of said snap switch for a solenoid coil disposed in said recesses an projecting the locking pin into locking poencircling said pin extension, and a laminar sition when the snap switch is on.

core supported by said coil with its plates Signed b me at Cleveland, Ohio, this in line with the plates of the laminar ex- 5th day of ugust 1924.

tension of said pm, said coil plates being CHARLES B. COATES. 

